textproduct: Rapid City

KEY MESSAGES

- Cooler weather prevails with precipitation chances through Thursday.

- Near-freezing temperatures overnight tonight and Tuesday and Thursday nights.

- Breezy Thursday with warmer weather for the weekend.

UPDATE

Issued at 958 PM MDT Mon Oct 12 2026

Light rain showers are pushing into southwestern SD courtesy of a weak upper wave ejecting over the Northern Plains. This light precip should continue to move northeastward through tonight as upper trof moves east. The cloud cover overnight should keep temps from dropping off too much, though we'll still see some chilly temps with lows dropping to the upper 30s across much of the area. Another chilly night on tap for Tuesday night into Wednesday with many areas approaching freezing. Some spots could see their first frost of the season early Wednesday, mainly across northwestern SD where cloud cover will be less.

Looking ahead to wind potential on Thursday, NAM progs 3-hr pressure rises of 3-4 mb, which will support breezy conditions. Though the stronger cold air advection and stronger 850-700 mb winds still looks to be displaced to the north and east of the forecast area.

DISCUSSION

(This Evening Through Monday) Issued at 1235 PM MDT Mon Oct 12 2026

Closed upper low is centered over southeastern OR with deep trough axis extending southward off southern CA coast. Water vapor imagery shows shortwave trough pushing north of the forecast area into ND with additional moisture and embedded vort maxes to our west along the eastern periphery of the low. A surface cold front stretches from southern MN through northeastern NE back into southwestern NE. Low clouds with mist/fog persist across the forecast area early this afternoon, although breaks in the clouds are becoming more numerous and expansive. Cold tonight with many areas falling into the mid to upper 30s.

The upper low is forecast to dig into the southwestern US with the trough axis shifting further east overnight tonight into Tuesday as broad upper level ascent overspreads the region. Light rain possible overnight tonight into Tuesday morning with ample cloud cover. Additional chances of light precipitation arrive early Wednesday through Thursday morning, with the best chances for widespread precipitation along the SD/NE border and southward.

Northern stream trough is forecast to drop out of Saskatchewan and Manitoba into the Upper Midwest early Thursday, swinging a strong cold front through the Northern Plains and Upper Midwest. A strong belt of 850-700 mb wind (~40-60 knots) will push into ND and central SD, sideswiping the forecast area. The strongest cold air advection will remain displaced east of the forecast area, where strongest winds can be expected. Deterministic NBM guidance continues to forecast 60+ mph wind gusts across portions of NW SD and the western SD plains Thursday afternoon. However, an ingredients-based approach coupled with ensemble guidance does not support winds this strong. The current forecast has Wind Advisory level winds (~45 mph) for portions of NW SD into the western SD plains Thursday afternoon and evening, although there is low confidence that this solution verifies; certainly, the High Wind (>60 mph) potential looks unlikely (probability < 15%).

Western ridging returns next weekend with above average temperatures forecast and dry conditions.

AVIATION

(For the 06Z TAFS Through 06Z Tuesday Night) Issued At 1016 PM MDT Mon Oct 12 2026

Widespread low cloud cover will lead to MVFR and IFR flight conditions through the forecast period. The localized LIFR conditions are possible in the Black Hills. Scattered showers are expected to move through NE WY and western SD overnight into Tuesday morning and decreasing into the afternoon.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.